This invention relates to multiple wire cables, and more particularly to small gauge wiring.
High speed data and signal transmission rates are limited by the characteristics of the conductors used for transmission. For electronic systems having separate components connected by a flexible multi-wire cable, the signal rate is limited not only by the nature of the flexible wires used for the cable, but by the means of connection between the cable and each component.
For high-rate applications, various high speed cabling may employed, including high performance coaxial wiring, twisted pair wires, or other configurations. Any selected cable has characteristics which limit its bandwidth and frequency capability for a given length, when permitting a certain level of signal loss. The initial bandwidth of the cable is reduced by the connections between cable and the circuit boards or other components used to make up a system. Discontinuities at junctions between different types of conductors can lead to reflections and ringing that require an extended time for clock cycles. Crosstalk between conductors also affects the maximum signal speed which is possible. Low Voltage Differential Signals (LVDS) to uses low voltages, typically under 5 volts, to limit switching noise that may generate electromagnetic interference with other electronic functions. Moreover, differences in transmission times for different lines may generate a skew, which also requires an extended period to encompass the range of times at which signals sent on each line arrive at their destination.
Normally, a connection between a cable and components requires a connector element at each end of the cable. Connectors have the facility to connect to the cable, as well as to a component such as a circuit board. Where the system requires detachability of cables and components, each end of the cable may include two mating connector components, one connected to the cable end, and the other connected to the circuit board. Such connectors each generate several discontinuities that limits bandwidth to below the theoretical capabilities of the cable itself. Such discontinuities occur where a circuit board connects to one connector portion, where that connector portion mates with the corresponding other connector portion, and where that connects with the cable wires. The accumulated effect of these discontinuities is believed to reduce frequency bandwidth by about one half in some cases.
In addition to their effect on performance, conventional connectors add significantly to the cost and bulk of high speed cable systems. The connectors must be installed on the component boards, as well as on the cable, requiring skilled labor costs. Cable wire and circuitry components may be provided by different suppliers, each with a part of a necessarily mating connector, making compatibility a concern. In addition, a cable manufacturer may have customers specifying different connectors, requiring the stocking of different components. Manufacturing costs are also significant in that cables with a multitude of conductors must be carefully assembled to ensure that each conductor is connected to the proper contact on each connector.
The present invention overcomes the limitations of the prior art by providing a cable with a number of wires. Each of the wires has a number of signal conductors encompassed by a dielectric sheath, and the sheath is encompassed by a conductive shield. The wires are arranged side-by-side in a row at an end of each wire, where a termination element is connected. The termination element has opposed major faces, with an array of first contacts on a first face, and an array of second contacts on the opposed face, each of the first contact being electrically connected to a corresponding second contact. Each of the signal conductors of the wire elements is connected to a corresponding one of the first contacts. The signal conductors may be a pair of wires arranged in parallel, so that all signal conductors are in a common plane.